Experimental and model analysis of the co-oxidative behavior of syngas feed in an Intermediate Temperature Solid Oxide Fuel Cell

• Published in: Journal of power sources Vol. 306; pp. 467 - 480
• Main Authors: Donazzi, A., Rahmanipour, M., Maestri, M., Groppi, G., Bardini, L., Pappacena, A., Boaro, M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 29-02-2016
• Subjects: Activation; Carbon monoxide; Ceria; Co-oxidation; Computer simulation; EIS; Electrolytic cells; IT-SOFC; Kinetics; Mathematical models; Polarization; Solid oxide fuel cells; Syngas; Synthetic fuels; Co-oxidation; Kinetics; IT-SOFC; EIS; Ceria; Syngas
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2015.12.038

By means of model analysis, we show that, in the presence of syngas, the electro-oxidation of H2 and that of CO occur in parallel and contemporarily on Samaria-doped Ceria (Sm0.2Ce0.8O1.9, SDC) Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). The activation of a co-oxidative route is a most distinguishing feature of Ce-based cells, compared to traditional SOFCs. SDC electrolyte supported IT-SOFCs with Cu–Pd-CZ80 composite anodes and LSCF cathodes were tested under a wide range of operating conditions. Polarization and EIS measurements were collected at 600 °C and 650 °C with syngas mixtures (2.3–0.4H2/CO ratio), H2/N2 mixtures (from 97 to 30% H2 v/v) and CO/CO2 mixtures (from 97 to 50% CO v/v). A 1D, dynamic and heterogeneous model of the cell was applied to analyze the polarization and the EIS curves. The kinetics of the reactions of H2 electro-oxidation, CO electro-oxidation and O2 reduction were individually investigated and global power law rates were derived. The syngas experiments were simulated on a fully predictive basis and no parameter adjustment, confirming that the polarization behavior could be best reproduced exclusively by assuming the presence of the co-oxidative route. The IT-SOFCs were also exposed to biogas mixtures, revealing that the dry-reforming reaction was active.
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•Ni-free, Ce-based IT-SOFCs are tested with syngas and biogas at 600 and 650 °C.•The electro-oxidations of CO and of H2 are active in parallel and contemporarily.•A 1D, dynamic, heterogeneous and physically-sound MEA model of the cell is applied.•The polarization curves and the EIS spectra are simulated based with the model.•Power law rate equations are derived for the electro-oxidation of H2 and of CO.